To study the possible role of interferon (IFN)-~ in ocular pathogenesis and specifically, the linkage between its induction of aberrant major histocompatibility complex (MHC) class II expression and predisposition to ocular autoimmune diseases, we generated transgenic mice with constitutive expression of IFN-gamma in the eye. Although the mouse has, up to this point proven to be a useful model, the rat is the preferred strain for the study of experimental autoimmune uveoretinitis (EAU). EAU is an animal disease that shares essential features with several human uveitic diseases such as sympathetic ophthalmia, birdshot retinochoriodopathy, Behcet's disease, and Vogt-Koyanagi-Harada (VKH) syndrome. Consequently, we have generated a IFN-gamma transgenic Sprague Dawley rat strain. In FY 1993- 1994 we focused on characterizing both the rat and mouse IFN-gamma transgenic models with the goal of establishing a comprehensive and complementary transgenic animal system that would be useful for studying the in vivo effects of IFN-gamma in the eye.